OSI computer programmer Liza Leitman who also competes in Olympic horse racing, is under threat of being kidnapped. Though she refuses to have any of Oscar's 'dwarfs' shadowing her, Oscar sends Steve Austin to tail her anyway.
Steve runs into an old flame, Barbara Thatcher, and learns she has recently become a widow. However, just as the two of them start to know each other once more, Barbara gets a call from the Bacarian Embassy, where her husband is hiding, alive and reasonably well.
A plane carrying a new kind of atomic warhead goes down on a remote South Pacific island, and the prototype seems to have fallen into the hands of a Japanese soldier who's has possibly been surviving on the island since WWII, convinced the war is still going on.
Dr. Chester Dolenz replaces Oscar Goldman with a new and improved robot. The impostor sends Steve Austin on a suicide mission to brave the defenses of the new Brahmin Institute. Austin decides to take along some new gadgets invented by fellow OSI agent and part time inventor Barney Barnes.
Steve Austin promises the sheriff of Kanab County to find and protect a rare and legendary cougar known as Taneha from a group of townsfolk intend on hunting down and killing the animal. He joins forces with a young girl E.J. Haskell, who has a personal vendetta against the wild cat.
Down on his luck boxer Johnny Dine has had plastic surgery to make him Steve Austin's double. He then infiltrates the OSI building when the real Austin is on a fishing holiday. After finding out the truth, Steve decides to turn the tables on Dine's superiors by posing as the boxer in turn.
US government weapon designer Harry Green is arrested on suspicion of selling his ideas to the opposition. His friend Steve Austin convinces Oscar Goldman that Harry could be the victim of an E.S.P. spy who by reading his mind managed to copy his designs. Oscar is then persuaded to take on a similarly gifted counterspy, young student Audrey Moss.
Steve Austin has proposed to Jaime Sommers and a wedding date is set. When Oscar Goldman plans on sending Jaime on her first assignment, Steve is very reluctant and insists on joining her. Furthermore Jaime keeps having bionic malfunctions and increasing headaches.
An Amassador's wife is kidnapped by the Independent Balinderry Army, I.B.A. for short. As Steve Austin heads for the small island republic to save her, he becomes involved with Unit 10 of the I.B.A. and it's mysterious leader, Commander 10.
Steve Austin's bionic legs are heavily damaged during a mission and while recuperating at Dr. Rudy Wells' hospital, he catches a glimpse of his fiancée Jaime, Sommers still alive but recuperating. It turns out Well's assistant Michael Marchetti used experimental cryogenics to preserve Sommers and nurse her back to health However, owing to some slight brain damage, Jaime no longer remembers anything about her past life.
Steve Austin takes the recuperating Jaime Sommers to their hometown of Ojai in an attempt to jog her memory. Unfortunately this only results in her getting violent headaches and confusing flashbacks. When she asks to be send on a mission in order to get her mind on something else, Steve goes along and the flashbacks only increase. Austin comes to the conclusion that it is his presence which is the cause of Jaime's condition.
Bitter explosive expert Robert Meyer arranges for the Liberty Bell to be stolen, rigs it with three bombs and demands five million dollars. Complications mount up and Steve Austin is forced to ask imprisoned bomb expert Linstrom to help defuse Meyer's handiwork.
Oscar and Rudy are performing a test on Barney Hiller to see if his bionic power can be turned on and off again when needed. A concerned Steve Austin proposes to keep an eye on Barney for the full 48 hours he has possession of his full strength. After competing in a car race, Barney loses control, panics and turns to a former O.S.I scientist who wants to use him for criminal purposes.
Several agents from the U.S. Treasury Department have died from snake bites while investigating an illegal moonshine ring in Morgantown, Georgia. Steve Austin volunteers to go undercover and pose as the leader of a rival gang.
Scientist Leon Jackson defected to the Soviet Union for the love of a woman but now wants to return to the states with his son Alex. However, Alex would rather stay with his friends, the Russian soldiers.
Somebody inside the OSI has been leaking top secret information and the trail leads to janitor Clark O'Flaherty. But when Steve confronts his former friend, O'Flaherty claims to be working for a another top secret organization, the OGA.